Process for preparation of silver oxide

ABSTRACT

A process for preparation of silver oxide with various shape and size using a silver complex compound having a special structure, includes 1) step of preparing a precursor solution including a silver complex compound obtained by reacting a silver compound with one or more mixture selected from the group consisting of an ammonium carbamate-based compound, an ammonium carbonate-based compound or an ammonium bicarbonate-based compound in the presence of a solvent; and 2) step of preparing silver oxide by reacting the precursor solution including the silver complex compound of step 1) with an oxidant. The shape and particle size of the silver oxide prepared according to the preparation process can be changed.

TECHNICAL FIELD

The present invention relates to a process for preparation of silveroxide with various shape and size by reacting a silver complex compoundhaving a special structure with an oxidant.

BACKGROUND ART

Ulmann's Encyclopedia of Ind. Chem., Vol. A24, 107 (1993) discloses thatsince silver, which is precious metal, is not easily oxidized but hasexcellent electric and thermal conductivity and further has a catalyst,an antibacterial activity and so on, silver compound such as silver (Ag)and silver oxide has been widely used in the industry overall such aselectrode material, alloys, platings, medicaments, photographs,electric/electronics, fibers, detergents, home appliances, and so on.

Silver oxide is a compound stable at a normal temperature, but has afeature that it is reduced into silver (Ag) using a decomposition byheating. A reduction reaction begins at 160° C., however the silveroxide having a slow response speed is required to be heated at 400° C.or more in order to give conductivity after the reduction is completed.

Japanese Patent Laid-Open No. Sho 56-69309 discloses the method toprepare silver oxide by adding aqueous silver nitrate (AgNO₃) solutioninto aqueous sodium hydroxide (NaOH) solution and then precipitating it.However, this method has disadvantage in that it is difficult to bedispersed and reduced at a low temperature due to aggregation. And, U.S.Pat. No. 7,201,888 discloses the method to prepare nano-sized silveroxide using silver nitrate (AgNO₃) and sodium hydroxide (NaOH) asoxidant and using fatty acid as surfactant on aqueous solution. However,this method fails to disclose a method to prepare particles of variousshapes.

DISCLOSURE Technical Problem

Therefore, in order to solve the problems, an object of the presentinvention is to provide a process for preparation of silver oxide havingvarious shapes and sizes by reacting a silver complex compound having aspecial structure with an oxidant.

Another object of the present invention is to provide a method tocontrol shapes and sizes of silver oxide to be prepared through the sortof oxidant and the change of content in oxidant used in preparing thesilver oxide.

Technical Solution

To achieve the above object, the present invention, which provides aprocess for preparation of silver oxide having various shapes and sizes,is characterized in that the silver oxide having various shapes andsizes is prepared by reacting a silver complex compound having a specialstructure with an oxidant.

Hereinafter, the method will be described for each step.

1) Step of preparing a precursor solution including a silver complexcompound obtained by reacting a silver compound with a mixture of atleast one selected from the group consisting of an ammoniumcarbamate-based compound, an ammonium carbonate-based compound or anammonium bicarbonate-based compound in the presence of a solvent; and

2) Step of preparing silver oxide by reacting the precursor solutionincluding the silver complex compound of step 1) with an oxidant.

Step 1): Preparation of a Precursor Solution Including a Silver ComplexCompound Having a Special Structure

A silver complex compound used for preparing silver oxide having variousshapes and sizes is prepared by reacting a silver compound representedby the formula 1 below with one or more mixture selected from the groupconsisting of an ammonium carbamate-based compound, an ammoniumcarbonate-based compound or an ammonium bicarbonate-based compoundrepresented by the formula 2, 3 or 4 below in the presence of a solvent.Ag_(n)X  [Formula 1]

[In the formula 1, n is an integer from 1 to 4 and X is a substituentselected from the group consisting of oxygen, sulfur, halogen, cyano,cyanate, carbonate, nitrate, nitrite, sulfate, phosphate, thiocyanate,chlorate, perchlorate, tetrafluoroborate, acetylacetonate, carboxylateand derivatives thereof.]

[In the formulas 2 to 4, R₁, R₂, R₃, R₄, R₅ and R₆ is hydrogen,aliphatic or cycloaliphatic (C1-C30)alkyl group, (C6-C20)aryl group,(C6-C20)aryloxy group, (C6-C20) ar (C1-C30)alkyl group,tri(C1-C30)alkylsilyl group, tri(C1-C30)alkoxy silyl group,tri(C6-C20)arylsilyl group, allyl group, or 3-membered to 7-memberedheterocyclic compound group, polymer compound group, hydroxyl group,(C1-C30)alkoxy group, (C1-C30)alkylamino group, independently from eachother, or R₁ and R₂ or R₄ and R₅ may be bonded independently from eachother by (C2-C6)alkylene, which includes or does not include heteroatom, to form a ring, the alkyl group or aryl group of R₁, R₂, R₃, R₄,R₅ and R₆ may further be substituted by aliphatic or cycloaliphatic(C1-C30)alkyl, (C1-C30)alkoxy, cyano, hydroxy, amino, (C6-C20)aryl,tri(C1-C30)alkylsilyl, tri(C1-C30)alkoxysilyl, tri(C6-C20)aryl silyl,allyl or carboxylic acid.]

The silver compound represented by the formula 1 is, for example, one ormore mixture selected from the group consisting of silver oxide, silverthiocyanate, silver cyanide, silver cyanate, silver carbonate, silvernitrate, silver nitrite, silver sulfate, silver phosphate, silverperchlorate, silver tetrafluoroborate, silver acetylacetonate, silveracetate, silver lactate, silver oxalate and derivatives thereof.However, the silver compound is not limited thereto.

Each substituent of R₁, R₂, R₃, R₄, R₅ and R₆ of the ammoniumcarbamate-based compound, the ammonium carbonate-based compound or theammonium bicarbonate-based compound represented by the formula 2, 3 or 4can be independently selected from the group consisting of hydrogen,methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, hexyl,ethylhexyl, heptyl, octyl, isooctyl, nonyl, decyl, dodecyl, hexadecyl,octadecyl, docodecyl, cyclopropyl, cyclopentyl, cyclohexyl, allyl,hydroxy, methoxy, hydroxyethyl, methoxyethyl, 2-hydroxypropyl,methoxypropyl, cyanoethyl, ethoxy, butoxy, hexyloxy, methoxyethoxyethyl,methoxyethoxyethoxyethyl, hexamethyleneimine, morpholine, piperidine,piperazine, ethylenediamine, propylenediamine, hexamethylenediamine,triethylenediamine, pyrrole, imidazole, pyridine, carboxymethyl,trimethoxysilylpropyl, triethoxysilylpropyl, phenyl, methoxyphenyl,cyanophenyl, phenoxy, tollyl, benzyl, derivatives thereof, polymercompounds such as polyallylamine and polyethyleneimine and derivativesthereof. However, they are not limited specifically thereto.

Specific examples of the ammonium carbamate-based compound representedby the formula 2 are one or more mixture selected from the groupconsisting of ammonium carbamate, ethylammonium ethylcarbamate,isopropylammonium isopropylcarbamate, n-butylammonium n-butylcarbamate,isobutylammonium isobutylcarbamate, t-butylammonium t-butylcarbamate,2-ethylhexylammonium 2-ethylhexylcarbamate, octadecylammoniumoctadecylcarbamate, 2-methoxyethylammonium 2-methoxyethylcarbamate,2-cyanoethylammonium 2-cyanoethylcarbamate, dibutylammoniumdibutylcarbamate, dioctadecylammonium dioctadecylcarbamate,methyldecylammonium methyldecylcarbamate, hexamethyleneiminiumhexamethyleneiminecarbamate, morpholinium morpholinecarbamate,pyridinium ethylhexylcarbamate, benzylammonium benzylcarbamate,triethoxysilylpropylammonium triethoxysilylpropylcarbamate andderivatives thereof. Specific examples of the ammonium carbonate-basedcompound represented by the formula 3 are one or more mixture selectedfrom the group consisting of ammonium carbonate, ethylammoniumethylcarbonate, isopropylammonium isopropylcarbonate, n-butylammoniumn-butylcarbonate, isobutylammonium isobutylcarbonate, t-butylammoniumt-butylcarbonate, 2-ethylhexylammonium 2-ethylhexylcarbonate,2-methoxyethylammonium 2-methoxyethylcarbonate, 2-cyanoethylammonium2-cyanoethylcarbonate, octadecylammonium octadecylcarbonate,dibutylammonium dibutylcarbonate, dioctadecylammoniumdioctadecylcarbonate, methyldecylammonium methyldecylcarbonate,hexamethyleneiminium hexamethyleneiminecarbonate, morpholiniummorpholinecarbonate, benzylammonium benzylcarbonate,triethoxysilylpropylammonium triethoxysilylpropylcarbonate,triethylenediaminium isopropylcarbonate and derivatives thereof.Specific examples of the ammonium bicarbonate-based compound representedby the formula 4 are one or more mixture selected from the groupconsisting of ammonium bicarbonate, isopropylammonium bicarbonate,t-butylammonium bicarbonate, 2-ethylhexylammonium bicarbonate,2-methoxyethylammonium bicarbonate, 2-cyanoethylammonium bicarbonate,dioctadecylammonium bicarbonate, pyridinium bicarbonate,triethylenediaminium bicarbonate and derivatives thereof.

Meanwhile, the preparation method and the sort of the ammoniumcarbamate-based compound, the ammonium carbonate-based compound or theammonium bicarbonate-based compound are not particularly limited. Forexample, the ammonium carbamate-based compound may be prepared from aprimary amine, a secondary amine, a tertiary amine or a mixture of atleast one thereof and carbon dioxide, as disclosed in U.S. Pat. No.4,542,214 (Sep. 17, 1985). An ammonium carbonate-based compound isobtained if 0.5 mole of water is used per 1 mole of amine and anammonium bicarbonate-based compound is obtained when 1 mole or more ofwater is used. At this time, the preparation may be performed undernormal pressure or applied pressure without a solvent or in the presenceof such solvent as water, alcohols like methanol, ethanol, isopropanoland butanol, glycols like ethylene glycol and glycerine, acetates likeethyl acetate, butyl acetate and carbitol acetate, ethers like diethylether, tetrahydrofuran and dioxane, ketones like methyl ethyl ketone andacetone, hydrocarbons like hexane and heptane, aromatic solvents likebenzene and toluene and halogen-substituted solvents like chloroform,methylene chloride and carbon tetrachloride or a mixture thereof. Thecarbon dioxide may be bubbled in gas phase or used in the form of dryice. Alternatively, the preparation may be performed in thesupercritical phase. Any other known methods can be applied in thepreparation of the ammonium carbamate-based derivative, the ammoniumcarbonate-based derivative or the ammonium bicarbonate-based derivativeused in the present invention, as long as the final structure is thesame. That is, solvent, reaction temperature, concentration, catalyst,etc. are not particularly limited in the preparation. Nor thepreparation yield is particularly limited.

A silver complex compound can be prepared by reacting the silvercompound prepared as above with the ammonium carbamate-based compound,the ammonium carbonate-based compound or the ammonium bicarbonate-basedcompound prepared as above. For example, at least one silver compoundrepresented by the formula 1 and the ammonium carbamate-based compound,the ammonium carbonate-based compound or the ammonium bicarbonate-basedcompound represented by the formulas 2, 3 or 4 or the mixture thereofare reacted under nitrogen atmosphere at normal pressure or appliedpressure without a solvent or in the presence of such solvent as water,alcohols like methanol, ethanol, isopropanol and butanol, glycols likeethylene glycol and glycerine, acetates like ethyl acetate, butylacetate and carbitol acetate, ethers like diethyl ether, tetrahydrofuranand dioxane, ketones like methyl ethyl ketone and acetone, aliphatichydrocarbons like hexane and heptane, aromatic solvents like benzene andtoluene and halogen-substituted solvents like chloroform, methylenechloride and carbon tetrachloride or a mixture thereof.

The precursor solution including the silver complex compound of step 1)may further include a dispersing agent to effectively disperseparticles. For example, 4000 series of EFKA, Disperbyk series of BYK,Solsperse series of Avecia, TEGO Dispers series of Degussa, Disperse-AYDseries of Elementis, JONCRYL series of Johnson Polymer, etc. may be usedfor this purpose. And, the dispersing agent is a mixture of at least oneselected from the group consisting of resin; surfactant; an aminecompound selected from a primary amine, a secondary amine or a tertiaryamine; the ammonium carbamate-based compound represented by the formula2; the ammonium carbonate-based compound represented by the formula 3;the ammonium bicarbonate-based compound represented by the formula 4; aphosphorus compounds like phosphine or phosphate; a sulfur compound likethiol or sulfide; and fatty acid.

More specifically, the resin may be selected and used at least one of anacryl resin such as polyacrylic acid and polyacrylic acid ester, acellulose resin such as ethyl cellulose, cellulose ester and cellulosenitrate, an aliphatic or copolymer polyester resin, a vinyl resin suchas polyvinylbutyral, polyvinylacetate and polyvinylpyrrolidone, apolyamide resin, a polyurethane resin, a polyether resin, a urea resin,an alkyd resin, a silicone resin, a fluorine resin, an olefin resin suchas polyethylene and polystyrene, a thermoplastic resin such as petroleumand rosin, an epoxy resin, an unsaturated or vinyl polyester resin, adiallylphthalate resin, a phenol resin, an oxetane resin, an oxazineresin, a bismaleimide resin, a modified silicone resin such as siliconeepoxy and silicone polyester, a thermosetting resin such as melamine, anacryl resin hardened by UV or electron beam, ethylene-propylene rubber(EPR), styrene-butadiene rubber (SBR) or a natural polymer such asstarch and gelatin.

Also, the surfactant may be an anionic surfactant such as sodium laurylsulfate, a nonionic surfactant such as nonylphenoxypolyethoxyethanol andFSN of Dupont, a cationic surfactant such as laurylbenzylammoniumchloride or an amphoteric surfactant such as lauryl betaine and cocobetaine.

Specific examples of the amine compound may be methylamine, ethylamine,n-propylamine, isopropylamine, n-butylamine, isobutylamine,isoamylamine, n-hexylamine, 2-ethylhexylamine, n-heptylamine,n-octylamine, isooctylamine, nonylamine, decylamine, dodecylamine,hexadecylamine, octadecylamine, docodecylamine, cyclopropylamine,cyclopentylamine, cyclohexylamine, allylamine, hydroxyamine, ammoniumhydroxide, methoxyamine, 2-ethanolamine, methoxyethylamine,2-hydroxypropylamine, methoxypropylamine, cyanoethylamine, ethoxyamine,n-butoxyamine, 2-hexyloxyamine, methoxyethoxyethylamine,methoxyethoxyethoxyethylamine, diethylamine, dipropylamine,diethanolamine, hexamethyleneimine, morpholine, piperidine, piperazine,ethylenediamine, propylenediamine, hexamethylenediamine,triethylenediamine, 2,2-(ethylenedioxy)bisethylamine, triethylamine,triethanolamine, pyrrole, imidazole, pyridine, aminoacetaldehydedimethyl acetal, 3-aminopropyltrimethoxysilane,3-aminopropyltriethoxysilane, aniline, anisidine, aminobenzonitrile,benzylamine, derivatives thereof and such polymer compounds aspolyallylamine and polyethyleneimine or derivatives thereof. Specificexamples of the ammonium compound are ammonium carbamate-based compoundssuch as ammonium carbamate, ethylammonium ethylcarbamate,isopropylammonium isopropylcarbamate, n-butylammonium n-butylcarbamate,isobutylammonium isobutylcarbamate, t-butylammonium t-butylcarbamate,2-ethylhexylammonium 2-ethylhexylcarbamate, octadecylammoniumoctadecylcarbamate, 2-methoxyethylammonium 2-methoxyethylcarbamate,2-cyanoethylammonium 2-cyanoethylcarbamate, dibutylammoniumdibutylcarbamate, dioctadecylammonium dioctadecylcarbamate,methyldecylammonium methyldecylcarbamate, hexamethyleneiminiumhexamethyleneiminecarbamate, morpholinium morpholinecarbamate,pyridinium ethylhexylcarbamate, triethylenediaminium isopropylcarbamate,benzylammonium benzylcarbamate, triethoxysilylpropylammoniumtriethoxysilylpropylcarbamate and derivatives thereof, such ammoniumcarbonate-based compounds as ammonium carbonate, ethylammoniumethylcarbonate, isopropylammonium isopropylcarbonate, n-butylammoniumn-butylcarbonate, isobutylammonium isobutylcarbonate, t-butylammoniumt-butylcarbonate, 2-ethylhexylammonium 2-ethylhexylcarbonate,2-methoxyethylammonium 2-methoxyethylcarbonate, 2-cyanoethylammonium2-cyanoethylcarbonate, octadecylammonium octadecylcarbonate,dibutylammonium dibutylcarbonate, dioctadecylammoniumdioctadecylcarbonate, methyldecylammonium methyldecylcarbonate,hexamethyleneiminium hexamethyleneiminecarbonate, morpholiniummorpholinecarbonate, benzylammonium benzylcarbonate,triethoxysilylpropylammonium triethoxysilylpropylcarbonate,triethylenediaminium isopropylcarbonate and derivatives thereof, andsuch ammonium bicarbonate-based compounds as ammonium bicarbonate,isopropylammonium bicarbonate, t-butylammonium bicarbonate,2-ethylhexylammonium bicarbonate, 2-methoxyethylammonium bicarbonate,2-cyanoethylammonium bicarbonate, dioctadecylammonium bicarbonate,pyridinium bicarbonate, triethylenediaminium bicarbonate and derivativesthereof. Also, the phosphorus compound may be one represented by thegeneral formula R₃P, (RO)₃P or (RO)₃PO, where R is a linear or branched(C1-C20)alkyl group or a (C6-C20)aryl group, Typical examples of suchphosphorus compound are tributylphosphine, triphenylphosphine,triethylphosphite and triphenylphosphite, etc. And, the sulfur compoundmay be butanethiol, n-hexanethiol, diethyl sulfide, tetrahydrothiophene,etc. Also, the fatty acid may be palmitic acid, stearic acid, oleic acidor linoleic acid, etc. The usage mount thereof is not particularlylimited.

The content of silver in the precursor solution including the silvercomplex compound having the special structure used in the presentinvention is not particularly limited. However, it is preferable thatits content is 0.1 to 50 wt %, more preferably 1 to 30 wt %. The usageamount of the dispersing agent is not particularly limited, either.However, it is preferable that its usage amount is 0.1 to 10 wt %, morepreferably 0.5 to 5 wt % of the contained silver.

2) Step of preparing silver oxide by reacting a precursor solutionincluding the silver complex compound of step 1) with an oxidant.

Step 2): Preparation of Silver Oxide by Oxidizing the Silver ComplexCompound Prepared by Reacting the Precursor Solution Including theSilver Complex Compound of Step 1) with the Oxidant

The oxidant may be diluted using a diluent and the usage amount of theoxidant is not particularly limited. However, the oxidant has anequivalent of 0.1 to 10, more preferably 1.5 to 5 by mole number ofsilver in the precursor solution including the silver complex compoundof step 1).

The oxidant may be an oxidative gas such as air, oxygen and ozone, astrong basic-alkali or alkaline earth metal compound such as NaOH, KOH,Ca(OH₂) or a mixture thereof, a peroxide such as hydrogen peroxide(H₂O₂), K₂S₂O₈, NaBO₃, KO₂, Na₂O₂, (NH₄)₂S₂O₈, Na₂S₂O₈, KHSO₅, H₂SO₅,(CH₃)₃CO₂H, and (C₆H₅CO₂)₂ etc., a peroxy acid such as HCO₃H, CH₃CO₃H,CF₃CO₃H, C₆H₅CO₃H, and m-ClC₆H₅CO₃H etc., an alkaline metal alkoxidesuch as NaOCH₃ and NaOCH₂CH₃ etc., a generally known oxidative inorganicacid such as nitric acid, sulfuric acid, I₂, FeCl₃, Fe(NO₃)₃, Fe₂(SO₄)₃,K₃Fe(CN)₆, (NH₄)₂Fe(SO₄)₂, Ce(NH₄)₄(SO₄)₄, NaIO₄, KMnO₄, and K₂CrO₄etc., a metal or a nonmetal compound. The oxidant may be used eitheralone or in combination of at least one thereof. However, the oxidant isnot particularly limited thereto.

The shape and particle size of the silver oxide are changed according tothe sort, concentration, mixing ratio, and mixing method of the oxidantused in the present invention.

As the diluent in the oxidation step, water, an alcohol such asmethanol, ethanol, isopropanol, 1-methoxypropanol, butanol, ethylhexylalcohol and terpineol, a glycol such as ethylene glycol and glycerine,an acetate such as ethyl acetate, butyl acetate, methoxypropyl acetate,carbitol acetate and ethylcarbitol acetate, an ether such asmethylcellosolve, butylcellosolve, diethyl ether, tetrahydrofuran anddioxane, a ketone such as methyl ethyl ketone, acetone,dimethylformamide and 1-methyl-2-pyrrolidone, a hydrocarbon such ashexane, heptane, dodecane, and paraffin oil, an aromatic solvent such asbenzene, toluene and xylene, a halogen-substituted solvent such aschloroform, methylene chloride and carbon tetrachloride, acetonitrile,dimethylsulfoxide or a mixture thereof may be used. The diluent is notparticularly limited thereto.

The silver oxide prepared based the process for preparation of thesilver oxide according to the present invention has various shapes suchas a sphere or a rod, etc., and various sizes of 100 to 500 nm, andfurther has excellent dispersibility, making it possible to be utilizedas raw material for electronic materials, an antibacterial agent, areaction catalyst, and a secondary battery, etc.

BRIEF DESCRIPTION OF DRAWING

The above and other objects, features and advantages of the presentinvention will become apparent from the following description ofpreferred embodiments given in conjunction with the accompanyingdrawings, in which:

FIG. 1 is the SEM image for the silver oxide of Example 1;

FIG. 2 is the SEM image for the silver oxide of Example 2; and

FIG. 3 is the SEM image for the silver oxide of Example 4.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention is described in further detailreferring to the examples. However, it will be appreciate that thoseskilled in the art, in consideration of this disclosure, may makemodifications and improvements within the spirit and scope of thepresent invention.

Example 1

41.98 g (56 mmol) of 2-ethylhexylammonium 2-ethylhexylcarbamate and 0.25g of isopropylammonium isopropylcarbamate as a dispersing agent weredissolved in 77.7 g of ethanol in a reactor equipped with a stirrer.Then, 5.36 g (23 mmol) of silver oxide (Kojima Chemical Co., Ltd) wasadded and reaction was performed at room temperature. At first, a blackslurry was obtained, but as the complex was formed, the color fadedgradually to be transparent. Finally, a colorless, transparent solutionwas obtained, after 2 hours of reacting. 100 g of ethanol in which 5.2 g(93 mmol) of KOH was dissolved was slowly added thereto for 1 hour. Asthe reaction proceeded in the transparent state, the reaction solutionturned into a light brown slurry and finally into a dark brown slurryafter the reaction was completed. The particles of the slurry werefiltered using a filter paper to be washed using ethanol until unreactedsilver complex compound and oxidant were completely removed, and thenwas decompressed under a vacuum drying oven at constant temperature of40° C. to completely remove solvents, thereby preparing a sphericalshaped silver oxide having a size of 200-500 nm. The SEM photograph ofthe silver oxide is shown in FIG. 1.

Example 2

41.98 g (56 mmol) of 2-ethylhexylammonium 2-ethylhexylcarbamate and 0.25g of isopropylammonium isopropylcarbamate as a dispersing agent weredissolved in 77.7 g of ethanol in a reactor equipped with a stirrer.Then, 5.36 g (23 mmol) of silver oxide (Technic Inc.) was added andreaction was performed at room temperature. At first, a black slurry wasobtained, but as the complex was formed, the color faded gradually to betransparent. Finally, a colorless, transparent solution was obtained,after 2 hours of reacting. 100 g of ethanol in which 3.7 g (93 mmol) ofNaOH was dissolved was slowly added thereto for 1 hour. As the reactionproceeded in the transparent state, the reaction solution turned into alight brown slurry and finally into a dark brown slurry after thereaction was completed. The particles of the slurry were filtered usinga filter paper to be washed using ethanol until unreacted silver complexcompound and oxidant were completely removed, and then was decompressedunder a vacuum drying oven at constant temperature of 40° C. tocompletely remove solvents, thereby preparing a spherical shaped silveroxide having a size of 100-300 nm. The SEM photograph of the silveroxide is shown in FIG. 2.

Example 3

41.98 g (56 mmol) of 2-ethylhexylammonium 2-ethylhexylcarbamate and 0.25g of isopropylammonium isopropylcarbamate as a dispersing agent weredissolved in 77.7 g of ethanol in a reactor equipped with a stirrer.Then, 5.36 g (23 mmol) of silver oxide (Kojima Chemical Co., Ltd.) wasadded and reaction was performed at room temperature. At first, a blackslurry was obtained, but as the complex was formed, the color fadedgradually to be transparent. Finally, a colorless, transparent solutionwas obtained, after 2 hours of reacting. 100 g of ethanol in which 2.6 g(46.5 mmol) of KOH and 1.9 g (46.5 mmol) of NaOH were dissolved wasslowly added thereto for 1 hour. As the reaction proceeded in thetransparent state, the reaction solution turned into a light brownslurry and finally into a dark brown slurry after the reaction wascompleted. The particles of the slurry were filtered using a filterpaper to be washed using ethanol until unreacted silver complex compoundand oxidant were completely removed, and then was decompressed under avacuum drying oven at constant temperature of 40□ to completely removesolvents, thereby preparing a spherical shaped silver oxide having asize of 100-500 nm.

Example 4

A rod shaped silver oxide having a thickness of 200-300 nm was preparedin the same manner as in Example 1 by adding the same amount of oleicacid as the dispersing agent, instead of isopropylammoniumisopropylcarbamate. The SEM photograph of the silver oxide is shown inFIG. 3.

Example 5

A rod shaped silver oxide having a thickness of 200-300 nm was preparedin the same manner as in Example 2 by adding the same amount of oleicacid as the dispersing agent, instead of isopropylammoniumisopropylcarbamate.

Example 6

A rod shaped silver oxide having a thickness of 200-300 nm was preparedin the same manner as in Example 3 by adding the same amount of oleicacid as the dispersing agent, instead of isopropylammoniumisopropylcarbamate.

Example 7

A spherical shaped silver oxide having a size of 300-500 nm was preparedin the same manner as in Example 1 after dissolving 10.66 g (56 mmol) oft-butylammonium t-butylcarbamate, instead of 2-ethylhexylammonium2-ethylhexylcarbamate, in 83.98 g of water, instead of ethanol.

Example 8

A spherical shaped silver oxide having a size of 300-500 nm was preparedin the same manner as in Example 2 after dissolving 10.66 g (56 mmol) oft-butylammonium t-butylcarbamate, instead of 2-ethylhexylammonium 2ethylhexylcarbamate, in 83.98 g of water, instead of ethanol.

Example 9

A spherical shaped silver oxide having a size of 300-500 nm was preparedin the same manner as in Example 3 after dissolving 10.66 g (56 mmol) oft-butylammonium t-butylcarbamate, instead of 2-ethylhexylammonium2-ethylhexylcarbamate, in 83.98 g of water, instead of ethanol.

The present invention relates to a process for preparation of silveroxide, and more particularly, to a process for preparation of silveroxide fine particles of various shapes using a silver complex compound.

The silver oxide prepared according to the present invention is reducedeven at low temperature of 400° C. or below and is excellent indispersibility. The shapes and sizes of the particles thereof can beeasily controlled so that a sphere or rod shaped silver oxide having asize below several hundred nanometers can be prepared by way of example.

What is claimed is:
 1. A process for preparation of silver oxidecomprising: preparing a precursor solution including a silver complexcompound obtained by reacting a silver compound represented by Formula 1below with one or more selected from an ammonium carbamate-basedcompound, an ammonium carbonate-based compound or an ammoniumbicarbonate-based compound represented by Formulas 2, 3 or 4 below inthe presence of a solvent; and preparing silver oxide by reacting theprecursor solution including the silver complex compound with anoxidant, wherein the oxidant is at least one selected from the groupconsisting of an oxidative gas, a peroxide, a peroxy acid, an oxidativeinorganic acid, an oxidative metal compound, and an oxidative nonmetalcompound;Ag_(n)X  {Formula 1} in the Formula 1, n is an integer from 1 to 4 and Xis a substituent selected from the group consisting of oxygen, sulfur,halogen, cyano, cyanate, carbonate, nitrate, nitrite, sulfate,phosphate, thiocyanate, chlorate, perchlorate, tetrafluoroborate,acetylacetonate, carboxylate and derivatives thereof,

in the Formulas 2 to 4, R₁, R₂, R₃, R₄, R₅ and R₆ is hydrogen, aliphaticor cycloaliphatic (C1-C30) alkyl group, (C6-C20) aryl group, (C6-C20)aryloxy group, (C6-C20) aryl (C1-C30) alkyl group, tri(C1-C30)alkylsilyl group, tri(C1-C30) alkoxy silyl group, tri(C6-C20) arylsilylgroup, allyl group, or 3-membered to 7-membered heterocyclic compoundgroup, polymer compound group, hydroxyl group, (C1-C30) alkoxy group,(C1-C30) alkylamino group, independently from each other, or R₁ and R₂or R₄ and R₅ may be bonded independently from each other by (C2-C6)alkylene to form a ring, the alkyl group or aryl group of R₁, R₂, R₃,R₄, R₅ and R₆ may further be substituted by aliphatic or cycloaliphatic(C1-C30) alkyl, (C1-C30) alkoxy, cyano, hydroxy, amino, (C6-C20) aryl,tri (C1-C30) alkylsilyl, tri (C1-C30) alkoxysilyl, tri (C6-C20) arylsilyl, allyl or carboxylic acid.
 2. The process for preparation ofsilver oxide according to claim 1, wherein the silver compoundrepresented by the formula 1 is a mixture of at least one selected fromsilver oxide, silver thiocyanate, silver cyanide, silver cyanate, silvercarbonate, silver nitrate, silver nitrite, silver sulfate, silverphosphate, silver perchlorate, silver tetrafluoroborate, silveracetylacetonate, silver acetate, silver lactate, silver oxalate andderivatives thereof.
 3. The process for preparation of silver oxideaccording to claim 1, wherein each substituent of R₁, R₂, R₃, R₄, R₅ andR₆ is independently selected from the group consisting of hydrogen,methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, hexyl,ethylhexyl, heptyl, octyl, isooctyl, nonyl, decyl, dodecyl, hexadecyl,octadecyl, docodecyl, cyclopropyl, cyclopentyl, cyclohexyl, allyl,hydroxy, methoxy, hydroxyethyl, methoxyethyl, 2-hydroxypropyl,methoxypropyl, cyanoethyl, ethoxy, butoxy, hexyloxy, methoxyethoxyethyl,methoxyethoxyethoxyethyl, hexamethyleneimine, morpholine, piperidine,piperazine, ethylenediamine, propylenediamine, hexamethylenediamine,triethylenediamine, pyrrole, imidazole, pyridine, carboxymethyl,trimethoxysilylpropyl, triethoxysilylpropyl, phenyl, methoxyphenyl,cyanophenyl, phenoxy, tollyl, benzyl polyallylamine, polyethyleneimineand derivatives thereof.
 4. The process for preparation of silver oxideaccording to claim 1, wherein the ammonium carbamate-based compoundrepresented by the Formula 2 is one or more selected from the groupconsisting of ammonium carbamate, ethylammonium ethylcarbamate,isopropylammonium isopropylcarbamate, n-butylammonium n-butylcarbamate,isobutylammonium isobutylcarbamate, t-butylammonium t-butylcarbamate,2-ethylhexylammonium 2-ethylhexylcarbamate, octadecylammoniumoctadecylcarbamate, 2-methoxyethylammonium 2-methoxyethylcarbamate,2-cyanoethylammonium 2-cyanoethylcarbamate, dibutylammoniumdibutylcarbamate, dioctadecylammonium dioctadecylcarbamate,methyldecylammonium methyldecylcarbamate, hexamethyleneiminiumhexamethyleneiminecarbamate, morpholinium morpholinecarbamate,pyridinium ethylhexylcarbamate, benzylammonium benzylcarbamate,triethoxysilylpropylammonium triethoxysilylpropylcarbamate andderivatives thereof; the ammonium carbonate-based compound representedby the Formula 3 is one or more selected from the group consisting ofammonium carbonate, ethylammonium ethylcarbonate, isopropylammoniumisopropylcarbonate, n-butylammonium n-butylcarbonate, isobutylammoniumisobutylcarbonate, t-butylammonium t-butylcarbonate,2-ethylhexylammonium 2-ethylhexylcarbonate, 2-methoxyethylammonium2-methoxyethylcarbonate, 2-cyanoethylammonium 2-cyanoethylcarbonate,octadecylammonium octadecylcarbonate, dibutylammonium dibutylcarbonate,dioctadecylammonium dioctadecylcarbonate, methyldecylammoniummethyldecylcarbonate, hexamethyleneiminium hexamethyleneiminecarbonate,morpholinium morpholinecarbonate, benzylammonium benzylcarbonate,triethoxysilylpropylammonium triethoxysilylpropylcarbonate,triethylenediaminium isopropylcarbonate and derivatives thereof; and theammonium bicarbonate-based compound represented by the Formula 4 is oneor more selected from the group consisting of ammonium bicarbonate,isopropylammonium bicarbonate, t-butylammonium bicarbonate,2-ethylhexylammonium bicarbonate, 2-methoxyethylammonium bicarbonate,2-cyanoethylammonium bicarbonate, dioctadecylammonium bicarbonate,pyridinium bicarbonate, triethylenediaminium bicarbonate and derivativesthereof.
 5. The process for preparation of silver oxide according toclaim 1, wherein the solvent is at least one selected from the groupconsisting of water, alcohols, glycols, acetates, ethers, ketones,aliphatic hydrocarbons, aromatic solvents, and halogen-substitutedsolvents.
 6. The process for preparation of silver oxide according toclaim 5, wherein the solvent is one or more selected from the groupconsisting of water, methanol, ethanol, isopropanol, butanol, ethyleneglycol, glycerine, ethyl acetate, butyl acetate, carbitol acetate,diethyl ether, tetrahydrofuran, dioxane, methyl ethyl ketone, acetone,hexane, heptane, benzene, toluene, chloroform, methylene chloride andcarbon tetrachloride.
 7. The process for preparation of silver oxideaccording to claim 1, wherein the precursor solution including thesilver complex compound further includes a dispersing agent.
 8. Theprocess for preparation of silver oxide according to claim 7, whereinthe dispersing agent is a mixture of at least one selected from thegroup consisting of resin; surfactant; an amine compound selected from aprimary amine, a secondary amine or a tertiary amine; the ammoniumcarbamate-based compound represented by the Formula 2; the ammoniumcarbonate-based compound represented by the Formula 3; the ammoniumbicarbonate-based compound represented by the Formula 4; a phosphoruscompounds; a sulfur compound; and fatty acid;

in Formulas 2 to 4, R₁, R₂, R₃, R₄, R₅ and R₆ is hydrogen, aliphatic orcycloaliphatic (C1-C30) alkyl group, (C6-C20) aryl group, (C6-C20)aryloxy group, (C6-C20) aryl (C1-C30) alkyl group, tri(C1-C30)alkylsilyl group, tri(C1-C30) alkoxy silyl group, tri(C6-C20) arylsilylgroup, allyl group, or 3-membered to 7-membered heterocyclic compoundgroup, polymer compound group, hydroxyl group, (C1-C30) alkoxy group,(C1-C30) alkylamino group, independently from each other, or R₁ and R₂or R₄ and R₅ are bonded independently from each other by (C2-C6)alkylene to form a ring, the alkyl group or aryl group of R₁, R₂, R₃,R₄, R₅ and R₆ are substituted by aliphatic or cycloaliphatic (C1-C30)alkyl, (C1-C30) alkoxy, cyano, hydroxy, amino, (C6-C20) aryl, tri(C1-C30) alkylsilyl, tri (C1-C30) alkoxysilyl, tri (C6-C20) aryl silyl,allyl or carboxylic acid.
 9. The process for preparation of silver oxideaccording to claim 8, wherein the resin is at least one of an acrylresin, a cellulose resin, a polyester resin, a polyamide resin, apolyether resin, a vinyl resin, a polyurethane resin, a urea resin, analkyd resin, a silicone resin, a fluorine resin, an olefin resin,petroleum, rosin, an epoxy resin, an unsaturated or vinyl polyesterresin, a diallylphthalate resin, a phenol resin, an oxetane resin, anoxazine resin, a bismaleimide resin, a modified silicone resin melamine,an acryl resin, a styrene-butadiene rubber or a natural polymer.
 10. Theprocess for preparation of silver oxide according to claim 8, whereinthe phosphorus compound is one represented by the Formulas 6 to 8 below,R₃P  Formula 6(RO)-₃P  Formula 7(RO)-₃PO  Formula 8 wherein R is a linear or branched (C1-C20) alkylgroup or a (C6-C20)aryl group.
 11. The process for preparation of silveroxide according to claim 8, wherein the sulfur compound is selected frombutanethiol, n-hexanethiol, diethyl sulfide or tetrahydrothiophene. 12.The process for preparation of silver oxide according to claim 8,wherein the fatty acid is selected from palmitic acid, stearic acid,oleic acid or linoleic acid.
 13. The process for preparation of silveroxide according to claim 1, wherein the oxidant has an equivalent of 0.1to 10, by mole number of silver in the precursor solution including thesilver complex compound.
 14. The process for preparation of silver oxideaccording to claim 1, wherein the oxidant is at least one selected fromthe group consisting of oxygen, ozone, NaOH, KOH, Ca(OH₂) H₂O₂, K₂S₂O₈,NaBO₃, KO₂, Na₂O₂, (NH₄)₂S₂O₈, Na₂S₂O₈, KHSO₅, H₂SO₅, (CH₃)₃CO₂H,(C₆H₅CO₂)₂, HCO₃H, CH₃CO₃H, CF₃CO₃H, C₆H₅CO₃H, m-ClC₆H₅CO₃H, NaOCH₃,NaOCH₂CH₃, nitric acid, sulfuric acid, I₂, FeCl₃, Fe(NO₃)₃, Fe₂(SO₄)₃,K₃Fe(CN)₆, (NH₄)₂Fe(SO₄)₂, Ce(NH₄)₄(SO₄)₄, NaIO₄, KMnO₄, and K₂CrO₄. 15.The process for preparation of silver oxide according to claim 1,wherein the oxidant is diluted with at least one solvent selected fromthe group consisting of water, an alcohol, a glycol, an acetate, anether, a ketone, a hydrocarbon, an aromatic solvent, and a halogenhydrocarbon.
 16. The process for preparation of silver oxide accordingto claim 15, wherein the solvent is at least one selected from the groupconsisting of water, methanol, ethanol, isopropanol, 1-methoxypropanol,butanol, ethylhexyl alcohol, terpineol, ethylene glycol, glycerine,ethyl acetate, butyl acetate, methoxypropyl acetate, carbitol acetate,ethylcarbitol acetate, methylcellosolve, butylcellosolve, diethyl ether,tetrahydrofuran, dioxane, methyl ethyl ketone, acetone,dimethylformamide, 1-methyl-2-pyrrolidone, hexane, heptane, dodecane,paraffin oil, benzene, toluene, xylene, chloroform, methylene chloride,carbon tetrachloride, acetonitrile and dimethylsulfoxide.